An avalanche warning is in effect 4 p.m. Tuesday above 4,000-feet in the Selkirk Mountains, West and East Cabinet Mountains, and the Silver Valley-Bitterroot Mountains.
Very dangerous avalanche conditions will develop overnight and last though Tuesday as heavy, wet snowfall transitions to heavy rain pushed by strong winds. Avoid travel in avalanche terrain during this period.
A potent atmospheric river characterized by near-historic moisture will introduce a firehose of moisture into North Idaho and Northwestern Montana. The rain line will rise to around 7,000 to 7,500 feet overnight Monday and will saturate recent snowfall and overload pre-existing weak snow layers.
It will be very likely for backcountry travelers to trigger avalanches and natural avalanches are likely. Avalanches can break wide across terrain features and run long distances to
lower elevations.